在Centos中用命令 yum install mysql安装数据库，但装完后运行mysqld启动mysql的时候提示找不到，通过 find / | grep mysqld 也没找到mysqld的目录，后来在Google上搜索下，才知道用yum安装时候mysql也有三个参数的。
yum install mysql，只是安装了mysql的client，如果你只安装了这一步，就会发现找不到mysqld。
yum install mysql-server，才安装了mysql的服务后台程序；当然还有一个MySQL-devel。
装上后就有mysqld了。
具体步骤如下：
yum install mysql yum install mysql-server yum install mysql-devel chgrp -R mysql /var/lib/mysql chmod -R 770 /var/lib/mysql service mysqld start
To start mysqld at boot time you have to copy support-files/mysql.server to the right place for your system PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER ! To do so, start the server, then issue the following commands: /usr/bin/mysqladmin -u root password 'new-password' /usr/bin/mysqladmin -u root -h LAMP.ORG password 'new-password' Alternatively you can run: /usr/bin/mysql_secure_installation which will also give you the option of removing the test databases and anonymous user created by default. This is strongly recommended for production servers. See the manual for more instructions. You can start the MySQL daemon with: cd /usr ; /usr/bin/mysqld_safe & You can test the MySQL daemon with mysql-test-run.pl cd mysql-test ; perl mysql-test-run.pl Please report any problems with the /usr/bin/mysqlbug script! The latest information about MySQL is available on the web at http://www.mysql.com Support MySQL by buying support/licenses at http://shop.mysql.comz